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Q41 - Gut Microbiota Across the Colorectal Cancer Progression

Theoretical 1 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license
Ecology

According to the evolutionary concepts, symbiosis is a general characteristic of living organisms and can help to understand complex features and phenotypes. Gut microbiota and host evolve in symbiosis and developed an integrative circuitry essential for their survival. This complex relationship resulted in a personal evolutionary adapted ecosystem. Recently developed genomics and metagenomics approaches helped to discover the link between the gut microbiota alteration with the host health and disease. Gagniere and his colleagues (2016) highlighted the unexpected role of human gut microbiota in colorectal cancer. More recently in a study conducted by Flemer and his colleagues (2018) it has been emphasized that the heterogeneity of colorectal cancer might be related to the types of gut microbiota that either predispose or offer resistance to the disease. Boxplots show the relative abundances of three bacterial groups from individuals with colorectal cancer (CRC), individuals with polyps (the intermediate stage between healthy and cancerous tissue which does not always turning to CRC) and healthy control (HC).

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. The microbiota compositional differences between patients with CRC and the control are secondary to the onset of cancer.
B. Changes in the abundance of the bacteria group 2 compared to the control are restricted to polyp.
C. Any bacterial group that populates the gut is in association with an increased risk of CRC.
D. The polyp-associated microbiota can be used as an indicator for individuals with higher risk of developing CRC.
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Question reproduced from IBO 2018, Theoretical Paper 1, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)